Dr. Rocha-Singh said this synergy between two pathophysiological systems – the activation of the sympathetic nervous system and the retention of sodium – relates to vascular resistance and excess volume, and to congestion and the perception of dyspnea.
When a person is in a reclining position, fluid shifts from the legs to the soft tissues. This effect is greater in patients with drug-resistant hypertension than in those with controlled blood pressure, and it occurs irrespective of body mass index and neck circumference, he said.
In a small study of patients who underwent renal denervation, 70% experienced not only blood pressure improvements but also decreases in the severity of sleep apnea as measured using the apnea-hypopnea index at 3 and 6 months’ follow-up, he said.
Additionally, in a small trial involving 27 patients who underwent pulmonary vein isolation or ablation of atrial fibrillation, 69% of those who also underwent renal denervation were free of recurrence of atrial fibrillation at 12 months, compared with only 29% of those who did not undergo renal denervation (J. Am. Coll. Cardiol. 2012;60:1163-70).
These encouraging findings contribute to what Dr. Rocha-Singh called a "tsunami of excitement" surrounding renal denervation. He noted that a quick Internet search identified more than 145 papers that have been published on the topic, and showed that more than 1,700 related provisional patents have been filed.
While, he – like Dr. Jaff – agreed that the enthusiasm must be tempered pending additional procedural and long-term data, he noted that the diversity of the primary and observed collateral benefits of renal denervation is something of a "vuja de" – the opposite of déjà vu.
"We have never experienced anything like this in our professional lives," he said.
Dr. Jaff is a consultant for numerous companies, including Medtronic, the maker of the Symplicity renal denervation device, but he is not compensated by Medtronic. He also has equity in numerous medical device companies, including one – Northwind Medical – that has a renal denervation strategy utilizing a novel mechanism. He is a board member for the nonprofit VIVA Physicians organization. Dr. Rocha-Singh is also a consultant or advisory board member for Medtronic, as well as for CardioSonic.